Core structure



May 4, 1937. BEN 2,079,393 CORE STRUCTURE Filed July 20, 1935 sSheets-Sheet 3 a?! 1937. F. H. BENGE 2,079,393

CORE STRUCTURE Filed July 20, ,1955 5 Sheets-Sheet 2 EwerzZr PatentedMay 4, 1937 tartar orrice tinental-Diamond Fibre Company,

Newark,

DeL, a, corporation of Delaware Application July 20, 1935, Serial No.32,459

12 Claims. (CI. 18-45) This invention relates to hollow articles and,more particularly, to such articles as pipes, pipe fittings and thelike. In my prior Patent No. 2,003,232, granted May 23, 1935, there isdisclosed and claimed a method of making an article of this class whichis composed of fibrous ma terial and an associated binder, and the wallsof which form a contiguous, homogeneous, coherent structure free oflines or planes of cleavage and uniformly massed by intermingling andcoherence of its constituent fibrous material and the binder. In themethod of the said patent, the desired article is formed by firstp-reforming at least one part of the article with loose, ragged edgesand then building up the remainder of the complete preform of thearticle in a manner to cause intermingling of the fibrous pieces at thesaid loose ragged edges so that an article of the character abovementioned is obtained. In my copending application, Serial No. 19,276,filed May 1, 1935, the improved article obtained by the method of mysaid patent is claimed.

The present invention has for its principal ob ject the provision of anovel method of forming the said article, which method is. in the natureof an improvement over that of my prior patent above mentioned. Ihepresent method eliminates the necessity of preiorming the article or anypart thereof, which is required in the method of my said patent. Bymeans of the present method, it is possible to mold the material ofwhich the article is to be formed directly about a core, at the sametime obtaining uniform distribution and density of the material aboutthe core so that the finished product has the desired characteristicsabove mentioned. It has been the practice in the past to use a fusiblecore in the molding of hollow articles, but in all prior methods ofwhich I am aware, it has been necessary to preform parts of the desiredarticle, and in the practice of all such prior methods, except that ofmy said prior patent, there have been obtained in the finished articleundesirable lines or planes of cleavage at the junctiu'e of thepreformed parts. This weal:-

ens the article and, in the case of an article such as a pipe fittingwhich is subjected to excessive stress at the threaded portions, thetendency is for the weakened article to fracture. This led to theinvention disclosed in my said patent. By the present method, however,there is provided a novel method and apparatus and a novel knockdowncore which conjunctively make practical the molding of the article aboutthe core in a single operation and without the necessity of pre formingany part of the article.

Although the invention is applicable generally to the manufacture ofhollow articles, since a pipe fitting is a very good example of thearticles which may be made by practicing the invention, I have chosen toillustrate and describe the invention in detail with reference to a Tpipe fitting. The invention may be clearly understood, therefore, byreference to the accompanying drawings, in which Fig. l is a perspectiveview of one of the core parts employed in accordance with the invention;

Fig. 2 is a perspective view of another of the core parts;

Fig. 3 is a perspective View of still another core part;

Fig. 4 is a perspective view of a further core part;

Fig. 5 is a perspective View of one of the parts of the core mold;

Fig. 6 is a sectional view taken through the core H mold and theassembled core therein;

Fig. l is a similar view showing the core after completion thereof;

Fig. 8 is a transverse sectional view taken along line 8-8 of Fig. '7;

Fig. 9 is a perspective view of the completed core;

Fig. 10 is a sectional view of the final mold with the complete coretherein illustrating the molding method; and

Fig. 11 is a similar view illustrating the method at a later stage.

The present invention contemplates broadly the use of any fibrousmaterial and an associated binder which may be found suitable.Preferably, however, small pieces of cotton base fabric impregnated withsynthetic resin of the phenolic type and, more especially,phenol-formaldehyde resin is used. Other fibrous materials which areapplicable for use are asbestos in fibre or paper form, wood pulp,paper, etc. The choice of the particular fibrous filling material willbe guided in any instance by the use for which the article is intended.Where the greatest possible strength is the controlling factor, smallpieces of fabric are employed. In any case where the finished article isto be subjected to corrosive action such as that of chemical action,there should be associated with the fibrous filling material sufiicientresin to protect the material from the corrosive action and to give astrong unitary article. In the case of cotton base fabric, there ispreferably associated with the fabric approximately to of resin. Thecotton fabric is preferably the resinimpregnated waste materialresulting from the manufacture of laminated! products, out into suitablesize. For example, the resin-impregnated fibrous pieces may vary widelyin size from A; inch at the smallest Width up to one inch at thegreatest width. If in a particular instance the amount of resinassociated with the fibrous filling material is not sufficient to bringthe resin content up to the desired amount, powdered resin in sufiicientamounts may be added. Regardless of the type of fibrous filler, theresin content of the finished article is preferably in the neighborhoodof 45% to 50%.

The type of binder most applicable is a synthetic resin either of thethermo-settin'g or thermo-plastic type. The particular binder chosen isgoverned by the use for which the article is intended, and in the caseof pipes or pipe fittings used to transport corrosive material, a bindermay be used which is chemically inert to the material to be transported.While phenol-formaldehyde resins are preferable for the transportationof acids, polybasic-acid-polyhydric-alcohol and urea-formaldehyde resinsare applicable for use for special purposes. Anilineformaldehyde resinsof the infusible thermoplastic type are especially applicable for thetransportation of alkaline solutions. In making the article of thepresent invention, the temperature, pressure and time conditions areselected which are applicable in conjunction with the particular resin.Hereinafter the invention will be described with the use ofphenol-formaldehyde resins as illustrative.

As well known, phenolic resins exist in an initial or soluble andfusible stage and in a final or insoluble and infusible stage. Theconversion of the resin from the initial to the final stage may beeffected by heat or by heat and pressure.

Referring now to the drawings, Figs. 1 to 4 show the parts of aknock-down core which may be employed in accordance with the presentinvention in the manufacture of a T pipe fitting.

The parts are shown in such relation to one another that their assemblymay be clearly envisioned from the following description. The partsshown in these figures are all formed of some relatively infusible metalor alloy, such as steel. In Fig. 1, there is illustrated a body part Iand in Fig. 2, there is illustrated a second body part 2, these partsbeing adapted to be brought into cooperative relation with one anotherto for i a T-shaped core body of the proper shape and size for theparticular T fitting. The main portion of the body part I is preferablyprovided with longitudinal corrugations 3 on its outer surface and thisportion is of smaller dimension than the desired completed core for areason which will appear hereinafter. The opposed ends 4 of the bodypart I are of smaller diameter than the main portion and these ends areadapted to support the threaded,

parts 5, one of which is shown in Fig. 4, it being understood that twoof these parts are provided, one for each of the ends *4. The parts 5are adapted to fit slidably and snugly over the ends t of the body parti. The main portion 6 of each of the threaded parts 5 is threaded asillustrated and conforms in contour with the threaded surface which itis desired to provide internally of the ends of the desired finishedproduct. These threaded parts 5 are each provided with an integral nutportion '1 bymeans oi which the parts may be removed from the acrea efinished article as will be explained hereinafter.

The second body part 2 has one end 8 formed as illustrated to cooperatewith the serrated portion 3 of the body part I. To this end, the end 8of the body part 2 is provided with serrations 9 which are complementaryto the serrations 4 so that the two body parts may be interlocked onewith another as seen in Fig. 8. It will be seen that the body part 2 maybe moved longitudinally of the body part I to obtain the proper relativepositions of the two body parts. The portion 8 of the body part 2 is ofsmaller dimension than the desired complete core for a reason which willbe explained presently.

The other end In of the body part 2 is of small diameter and is adaptedto receive a threaded part H which is similar in all respects to thethreaded parts 5 and is provided to form the third threaded portion ofthe desired T fitting.

' Referring now to Figs. 5 to 3, in Fig. 5 there is illustrated one ofthe parts H of a two-part mold, the mold being shown in assembled formin Fig. 8 which shows the other part l3. These two mold parts aresimilar and are provided with interlocking pins and recesses. The moldpart l2 is provided with the tapered pins l4, while the mold part It isprovided with recesses 15 adapted to receive the pins Hi. The mold partI3 is also provided with an opening l5 through which fused metal may bepoured as described hereinafter.

It will be seen from Fig. 5 that the mold parts; are provided withrecesses I? which are adapted to receive the threaded portions of thethreadedgl core parts 5 and H, and there are also provided"; recesses l8which are adapted to receive the nut: portions 1 of the threaded coreparts and recesses L! which are adapted to receive the extending;- ends4 and ill of the body parts of the core.

In practicing the method of the invention, the;

first step is to assemble the core parts illustlzatedi in Figs. 1 to 4and to place these assembled parts; in the core mold. Obviously, thismay be done; by first placing the assembled parts in one-half. of themold, for example the mold part I! shown; in Fig. 5, and then applyingthe other half of? the mold. It will be understood that the; two

mold parts may be secured tightly together by/ any suitable means suchas a clamp. The; core.- mold with the assembled core parts therein is;shown in Fig. 6. The internal contour ofgthercoreg mold about theportions 3 and 8 of the, core-parts: I and 2 conforms in shape with the;desired: completed core.

A metal of relatively low melting point, for example 450 to 500 R, suchas lead, is then poured through the opening l6 into the space 20surrounding the portions 3 and 8 of the solid core parts. When allowedto harden, this metal builds up the body of the core to the desiredshape and dimension and, at the same time, it secures the assembled coreparts together. The serrations of the portion 3 hold the lead or likemetal securely and prevent this relatively soft metal from sliding offthe core parts. The com pleted core prior to removal from the core moldis shown in Fig. 7, the molded or cast metal being I completed core isremoved. The completed core is shown, after removal from the mold, inFig. 9. It will be seen thatthis core conforms in shape with theinternal surface or surfaces desired in the finished article.

Referring now to Figs. and 11, there is illustrated the molding of thedesired article which, of course, constitutes the essential part of theinvention. The mold used for this purpose may comprise a hollow ring orouter casing 22 and a split tapered mold 23, the complementary parts ofwhich are adapted to fit snugly within the ring or casing 22 inWell-known manner. The two part mold 23 is adapted to receive thecompleted core, as clearly illustrated, and when the core is in place inthe mold, there is provided a space 2 which conforms in shape anddimension with the walls of the desired article. It will be seen thatthe ends 4 of the solid core part I, and the nut portions 1 of the parts5, are seated snugly in recesses in the mold 23. Thus the end portionsof the solid core part I serve to support the completed core in themold, maintaining the core in proper position throughout the moldingrecess.

A sleeve 25 is placed over the extended end Iii thus forming an annularreservoir 26 which communicates through a narrow annular opening 27 withthe channel-like space 2 3. An annular plug 28 is adapted to fit snuglyand slidably into the annular reservoir 25.

Following the method of the invention, after the completed core has beenassembled in the mold as illustrated in Fig. 10, the material of whichthe article is to be formed is placed in the reservoir 26. In thepreferred form of the invention, this material may consist of smallresin-impregnated fibrous pieces as above mentioned. It will beunderstood that the resinous binder is in its initial soluble andfusible stage. The resinimpregnated pieces may be placed in thereservoir 26 until the said reservoir is substantially filled. Thereservoir may be of such size as to hold sufiicient material tocompletely form the desired article when it is filled with suchmaterial.

Pressure is now applied to the material in the reservoir by means of theannular plug 28 and the material is thus caused to flow through theannular opening 2'! into the space 25 about the core. The restrictedannular opening 21 allows only a low rate of flow of material into thespace 24 and thus the process comprises a slow flowing of the materialinto the space 24 and around the core. In this manner, the material isdistributed evenly about the core, the small fibrous pieces beinginterspersed or intermingled with one another, and there results ahomogeneous wall structure of even density, as shown in Fig. 11. It isimportant to note that the provision of the reservoir 26 and therestricted opening 21 enables the successful attainment of the desiredobject. By the use of these features and the particular core structure,it is possible to completely mold the material about the core in thedesired manner without distorting the core. By the use of solid coreparts, as above described, the core is strengthened or reinforced and iscapable of withstanding the pressure to which it is subjected. At thesame time, however, the stress or force to which the core is subjectedand which tends to distort the core is maintained at a minimum by reasonof the particular method employed.

After the article is completely molded about the core, as shown in Fig.11, the conversion of the resin to its final or insoluble and infusiblestage may be efiected by applying heat in conjunction with the pressureof the mold. The

temperature will depend upon the mold pressure and the time of theconversion process or vice versa, but in general a temperature of about350 F. will be applied until the phenol-formaldehyde resin is completelycured. Of course, in any case the temperature should not rise to themelting point of the fusible metal of the core. It will be understood,too, that the heating step will vary with various binders that might beused. Preferably, the outer casing 22 is provided with a steam jacket 29having pipes 30 leading thereto by which the heating medium may beapplied. In this manner, the entire mold is very readily heated to thedesired temperature. Inasmuch as the mold is of substantial height, itwould be impractical to depend upon traversal of the heat byconductivity from one part of the mold to another and it is, therefore,desirable to employ a heating jacket as illustrated.

After the binder has been completely cured and the finished article hasthus been produced, the said article with the core therein is removedfrom the mold. The threaded parts 5 and Il may be readily removed byunscrewing them from the finished article by means of a wrench or thelike applied to the nut portions 1. Sufficient heat is then applied tothe fusible metal 2| to melt the same. This may be done by simplydirecting a torch flame onto the fusible metal. This frees the othersolid parts of the core and enables their removal from the finishedarticle. It will be seen that the solid core parts, as well as thefusible metal, may be used repeatedly in the manufacture of the desiredarticle.

By means of this method, an article is produced having the desiredcharacteristics above mentioned. It will be seen that the finishedarticle requires no machining or like operation since the article isformed in its entirety including the threaded portions thereof. It willbe seen also that the method is simple and inexpensive. It will beunderstood, of course, that the invention is not limited by the presentdisclosure but is susceptible to such variations 0r modifications as mayoccur to persons skilled in the art.

I claim:

1. In a core structure for use in the molding of hollow articles, suchas pipe fittings, an inner core part formed of relatively infusiblematerial,

an outer core part formed of similar material re- 1 movably carried upona portion of said inner part and having an exterior contour similar tothe internal surface desired on a portion of said article, and a bodyformed of relatively fusible material surrounding another portion ofsaid inner part and securing said outer part on said inner part, saidbody having an exterior surface similar to the interior surface desiredon another portion of said article.

2. In a core structure for use in the molding of hollow articles, suchas pipe fittings, an inner core part formed of relatively infusiblematerial and having a portion with a fluted surface, an outer core partformed of similar material removably carried upon another portion ofsaid least one internally threaded end, an inner core part formed ofrelatively infusible material, an outer core part formed of similarmaterial removably carried upon an end portion of said inner part andhaving an exterior threaded contour similar to the internal threadedsurface desired at the end of said article, and a body formed ofrelatively fusible material surrounding another portion of said innerpart and securing said outer part on said inner part, said body havingan exterior surface similar to the interior surface desired on anotherportion of said article.

4. In a core structure for use in the molding of hollow articles, suchas pipe fittings, an inner core part formed of relatively infusiblematerial, outer core parts formed of similar material removably carriedupon the end portions of said inner part, each of said outer .partshaving an exterior contour similar to the internal surface desired on anend portion of said article, and a body formed of relatively fusiblematerial surrounding the intermediate portion of said inner part andsecuring said outer parts on said inner part, said body having anexterior surface similar to the interior surface desired on anintermediate portion of said article.

6. In a core structure for use in the molding of hollow articles, suchas pipe fittings, an inner core part formed of relatively infusiblematerial, outer core parts formed of similar material removably carriedupon the end portions of said inner part With the ends of said innerpart ex tending beyond said outer parts, each of said outer parts havingan exterior contour similar to the internal surface desired on an endportion of said article, and a body formed of relatively fusiblematerial surrounding the intermediate portion of said inner part andsecuring said outer parts on said inner part, said body having anexterior surface similar to the interior surface desired on anintermediate portion of said article.

6. In a core structure for use in the molding of hollow articles, suchas pipe fittings, an inner core part formed of relatively infusiblematerial and having a fluted intermediate portion, outer core partsformed of similar material removably carried upon the end portions ofsaid inner part, each of said outer parts having an exterior contoursimilarto the internal surface desired on an end portion of saidarticle, and a body formed of relatively fusible material surroundingthe fluted portion of said inner part and securing said outer parts onsaid inner part, said body having an exterior surface similar to theinterior surface desired on an intermediate portion of said article.

7, In a core structure for use in the molding of hollow articles, suchas pipe fittings, having internally threaded ends, an inner core partformed of relatively infusible material, outer core parts formed ofsimilar material removably carried upon the end portions of said innerpart, each of said outer parts having an exterior threaded contoursimilar to the internal threaded surface desired on an end portion ofsaid article, and a body formed of relatively fusible materialsurrounding the intermediate portion of said inner part and securingsaid outer parts on said inner part, said body having an exteriorsurface similar to the interior surface desired on an intermediateportion of said article.

8. A core structure for use in the molding of hollow articles, such as Tpipe fittings, comprising a plurality of complementary inner core partsformed of relatively infusible material, a plurality of outer core partsformed of similar material removably carried upon the end portions ofsaid innerparts, each of said outer parts having an exterior contoursimilar to the internal surface desired on an end portion of saidarticle, and a body formed of relatively fusible material surroundingthe intermediate portions of said inner parts and securing the variousparts together as an integral core, said body having an exterior surfacesimilar to the interior surface desired on the intermediate portion ofsaid article. 7 Q

9. A core structure for use in the molding of hollow articles, such as Tpipe fittings, comprising a plurality of interlocking complementary inercore parts formed of relatively infusible ma-. terial, at least one ofsaid parts having an intermediate fluted surface, a lurality of outercore end portionof said article, and a body formed of relatively fusiblematerial surrounding the intermediate portions of said inner partsandfse curing the various parts together as an integral core, said bodyhaving an exterior surface similar to the interior surface desired onthe intermediate portion of said article. i 10. A core structure for usein the moldingof hollow articles, such as T pipe fittings, comprising apair of interlocking complementary inner core parts formed of relativelyinfusible material and arranged at right angles to one another, at leastone of said parts having an intermediate fluted surface, a plurality ofouter core parts formed of similar material removably carried upon theend portions of said inner parts, each of said outer parts having anexterior contour similar to the internal surface desired on an endportion of said article, and a body formed of relatively fusiblematerial surrounding .the intermediate portions of said inner parts andsecuring the various parts together as an integral core, said bodyhaving an exterior surface similar to the interior surface desired onthe intermediate portion of said article. j v 11. In a core structurefor use in the molding of hollow articles, such as pipe fittings, havingat least one internally threaded portion, at least one core part formedof relatively infusible material and having an exterior threaded contoursimilar to the internal threaded surface desired on said article, and abody formed oflrelatively fusible material secured to said part andhaving an exterior surface contour complementary to said threadedcontour and similar to the internal surface desired on another portionof said article. 12. In a core structure for use in the molding ofhollow articles, such-as pipe fittings, having a plurality of internallythreaded portions, a plurality of core parts formed of relativelyinfusible material and having exterior threaded contours similar to theinternal threaded surfaces desired on said article, and a body formed ofrelatively fusible material securing said parts together and having anexterior surface contour complementary to said threaded contours andsimilar to the internal surface desired on another portion of saidarticle.

FRANK H. BENGE.

